Function Reference and Table Sort

Question

I have a table that I use to track numerical data to a fixed size table.
After adding new data I sort the columns, for example in descending order.
My question is this, is it possible to specify the references in say the Average Function to refer to the same cells, eg the bottom 10, in the table and not be affected by the sort. Another way to describe this is that I would like to always average the bottom 10 cells and not have this change with the sort command.
thank you

Answer 1

Thanks to both of you.
In fact I was not satisfied.
the initial formula assumes that every cells in the column are filled (minus the bottom one used ase a fake footer)
For those whose use doesn't match this requirement, here is an enhanced one.
=AVERAGE(OFFSET($A$1,COUNT(B)+1-10,1,10,1))
I wrote +1-10 to make clear what is done:
+1 because the COUNT() function doesn't count the header row
-10 to leave 10 filled cells in the calculated range
Jerry : it seems that you missed that I often used this function to define a range of cells. I must say thank you to Bugs Hunters because some months ago I asked them because I didn't correctly understood the function's behavior and they took time to explain what I missed.
While working on this question, I encountered what I feel as a gap in the Help. It states:
To copy cells within or between tables, drag selected cells while holding down the _Option key_ . Any values in the destination cells are replaced.
They forgot to add: "and then drag the selection by its border" as it is written for the move feature.
An alternate protocol works to move a group of cells:
select such a group
press the shift key.
drag the selected block where we want.
Yvan KOENIG (from FRANCE mardi 14 octobre 2008 19:31:42)